Code Review - how to do it better?

Room B3

Saturday from 14:30 til 15:20

The more complex application is the more people are working on it. The more code they're are creating, the more important is to take care of quality of this code. And Code Review is a great practice to doing it.
Yet, it happens really often that after a while, when your eagerness decreases and the amount of reviews grow, many people starts to complain.
They're looking for excuses to not have a time for the reviews. For doing it carelessly. Is it a problem? Only if you won't react. Because there's a room for improvements in here!